Effect of carbon fiber surface treatment on Cu electrodeposition: The electrochemical behavior and the morphology of Cu deposits

The relationship between surface functional groups and electrochemical behaviors of polyacrylonitrile (PAN)-based carbon fibers (CFs) differentiated by oxidation treatment in air was studied. The chemical character of the CFs surface was estimated by X-ray photoelectron spectroscopy (XPS) and the electrochemical behavior of treated CFs in CuSO₄ plating solution was studied by electrochemical setup. The influence of functional groups on the morphology of copper deposits was characterized by field-emission scanning electron microscopy (FESEM). It was found that the O/C atomic ratio rose rapidly from 23.05% (as-received carbon fibers) to 42.83% as the oxidation temperature was increased to 400 °C and the content of -CO was the highest. Concentrations and types of the functional groups on CFs surface showed a close connection with the electrochemical response of CFs in CuSO₄ plating bath. It was showed that Cu electrodeposition was the interaction of applied voltage and the reduction of surface functional groups. With the functional groups increased, the quantities of the Cu nuclei increased, further the morphology of deposited Cu was affected.